To extend your play session a bit longer, there are thirty Harley Quinn balloons you can seek out and destroy. This is literally the only side activity in this DLC. There are no new Riddler challenges to puzzle over, no phone calls to answer, no optional villains to hunt down, and no other subplots to distract you. Harley is truly the focus here.

It's a shame, then, that she's so easy as a boss. You will fight her once as Robin and once as Batman, and you'll have much more trouble whittling down her guards than you will actually beating her. This is made more disappointing by the fact that there are some legitimately challenging segments throughout the story. It seems odd that the whole story would revolve around Harley, only to basically hold your hand through her final showdown.

In the end, Harley Quinn's Revenge is an excuse to go back to a game you probably still haven't earned 100% completion in yet. It extends the game by a couple hours and gives you face time with the Boy Wonder. If that doesn't appeal to you, then by all means skip it. But for those of us who've been dying for an excuse to return to Arkham City, we finally have a pretty good one. The ten-dollar price tag might be a tad steep for the amount of content here, but I'd venture to say it's ultimately worth it. And really, I can't think of a better Batman-related activity to take part in while you're waiting for The Dark Knight Rises to hit theaters.